1. Field of the Invention
The invention is based on a fluid pump having a motor housing and on a method for producing a motor housing for a fluid pump useful, for example, as a circulating pump in a heating or cooling system of a motor vehicle.
2. Description of the Prior Art
The principle of separating the stator inverter with a tube that makes it possible to dispose the rotor in such a way that it is immersed in a coolant is known from German patent DE 37 02 028 C2.
A more-detailed description of such a fluid pump can be found in German patent disclosure DE 44 11 960 A1. The fluid pump shown in this reference has a bell-shaped rotor, whose cylindrical interior is engaged by the stator. A tubular or cup-shaped wall extends between the rotor and the stator, and a shaft about which the rotor is rotatably suspended is let into the bottom of a cup.
The anchoring of the shaft extends only a slight depth into the interior of the cylindrical hollow chamber, because almost the entire space in this chamber is required for accommodating the stator. The cylindrical wall between the stator and the rotor is very thin, for the sake of attaining a small gap width and thus low magnetic circuit losses. This impairs the stability of the suspension of the rotor.
A printed circuit board with a commutation circuit for supplying electric current to the stator can be disposed only in the axial extension of the stator, which thus increases the installation depth of the fluid pump.
German patent application 199 34 382 has also proposed using a fluid pump with a motor that has a claw pole stator. This claw pole stator comprises a winding and two claw baffles with claws. The individual parts have to be assembled in a plurality of assembly steps and fixed on the motor housing. Because of tolerance, an air gap is created between the claw pole stator and the motor housing, which makes it more difficult to dissipate a heat loss from the winding to a medium pumped in the fluid pump and makes it harder to achieve low magnetic circuit losses.
The fluid pump of the invention having a motor housing, and the method for producing a motor housing for a fluid pump, have the advantage over the prior art that the operating properties are improved and the number of assembly steps is reduced, both in a simple way.
By injecting claw baffles, the advantages obtained, because of heat transfer without an air gap, that a heat loss from a winding and claws can be better dissipated to a fluid flowing in a tube.
It is especially advantageous to inject or mold the claws or claw baffles into a motor housing, since as a result fewer parts have to be assembled. It is advantageous to inject metal connecting parts into the motor housing, since once again the installation in the motor housing is made unnecessary, and a passage through the connecting parts is simultaneously well sealed off.
It is also advantageous to inject a stamped grid into the motor housing; the stamped grid makes an electrical connection from and to a printed circuit board, and as a result it is no longer necessary for electrical connecting lines to be put in place and secured.
It is advantageous to spray-coat the claw pole stator in such a way that heat radiation from the winding in the region of the at least one printed circuit board is reduced, since this improves the service life and operating conditions of the printed circuit board.
It is advantageous for the winding to be wound directly onto the motor housing, because then no additional winding holder has to be used.
A short-circuit ring is advantageously mounted on the motor housing.